Buying a baby royal.

Main causes for them not to feed IMO are:

Too much time in between being offered food.

Too much handling at first.

Tempertures are wrong.

When buying a new baby my advice would be:

When you get home after collecting them double check that your set up and ALL your TEMPS are suitable for your new little one. If you want to take a few pics for the forums and Facebook do that now. After that all handling to a MINIMUM. You want your baby to settle down so leave them be, just a quick peak daily to make sure all is ok. After 3-4 days offer food but still no handling unless you have to clean. IMO babies that are left over 9-12 days without being offered food tend to go off feeding for a while. The KEY is to get them FEEDING regularly THEN you can slowly introduce them to being handled. Getting them feeding regularly is your first priority and much more important than you handling your new baby no matter how impatient you are.

Quarantining new additions.

If you already have reptiles at home you will need to quarantine your new additions. Best way to do this is a separate room. Now most people don't have this luxury to be able to put new additions into separate rooms.

If you have to use the same room you can still abide by quarantine procedures but you need to be very strict with your method.

Treat with a mite spray whether they have them or not plus the tub or bag they came in or throw them out.

Put new additions as far away as you can from your resident reptiles.

Deal with the newbies last ie water,feeding or cleaning.

Disinfect tongs and other equipment or buy a second set just to use on your new additions.

When handling make sure you disinfect your hands in between handling each one and try not to let them go onto your clothes.

Disinfect any area they've been on.

Don't put them in or let them touch your other snakes until the end of your quarantine period. 

Quarantine period should not be less than 3 months.